I'm looking to put an AR together and I would like to know the difference and advantages of a regular barrel, heavy barrel and super bull barrel. I was thinking of installing the heavy barrel. Is it true that it lasts longer?

What do you plan on doing with it? I would only buy a bull barrel for a varmint or benchrest gun.

Heavy barrels only exist because they require less work to make. If I'm going to be shooting off hand I avoid anything heavy barrel profile and fatter. In fact my next build is probably going to be a pencil barrel.